Summary of Signigicant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2012

Accounting Policies [Abstract]

Property and Equipment

(in thousands)	June 30, 2012			December 31, 2011
Property and Equipment
Proved oil and gas properties	$	4,715,417		$	4,343,867
Unproved oil and gas properties	89,005			84,146
Furniture, fixtures, and other equipment	41,062			38,832
Less – Accumulated depreciation, depletion, and amortization	(2,722,546		)	(2,599,079		)
Property and Equipment, Net	$	2,122,938		$	1,867,766

Accounts Payable and Accrued Liabilities

	June 30, 2012		December 31, 2011
Trade accounts payable (1)	$	45,183	$	42,080
Accrued operating expenses	15,606		15,833
Accrued payroll costs	8,111		14,345
Asset retirement obligation – current portion	9,656		9,279
Accrued taxes	8,610		7,604
Other payables	2,237		6,825
Total accounts payable and accrued liabilities	$	89,403	$	95,966

(1) Included in “trade accounts payable” are liabilities of approximately $23.7 million and $18.7 million at June 30, 2012 and December 31, 2011, respectively, for outstanding checks.

Accumulated other comprehensive income and related tax effects

	Gross Value			Tax Effect			Net of Tax Value
Other comprehensive loss at December 31, 2011	$	—		$	—		$	—
Change in fair value of cash flow hedges	1,171			426			745
Effect of cash flow hedges settled during the period	(1,171		)	(426		)	(745		)
Other comprehensive income at June 30, 2012	$	—		$	—		$	—

Roll-forward of our asset retirement obligations

	2012
Asset Retirement Obligation recorded as of January 1	$	76,393
Accretion expense	2,274
Liabilities incurred for new wells and facilities construction	566
Reductions due to sold and abandoned wells	(80		)
Revisions in estimates	1,475
Asset Retirement Obligation as of June 30	$	80,628